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Guitars: The Sounds and Science

HP Newquist, Executive Director and Founder of the National GUITAR Museum and Prabir Mehta, guitarist for local rock and roll band Goldrush, are both passionate about guitars. I had the opportunity to talk with them recently about the guitar’s history and engineering while visiting the exhibition “GUITAR: The Instrument that Rocked the World” at the Science Museum of Virginia. This is a great exhibition to visit over the holidays for it runs through January 6, 2013. Watch theScience Matters video featuring Newquist and Mehta sharing their thoughts about the world's most popular instrument.

HP Newquist talks about the science and sound of the guitar:

Structural engineering
“There’s a lot more to a guitar than simply a box that has some wires on top of it. The design of the acoustic guitar involves technical and structural engineering and specifications that require a lot of bracing. This is because an acoustic guitar is a wooden box that’s held together only with glue and has strings that run across the top of it. Those strings can exert as much as 200 lbs. of pull. And yet, the wooden box that’s as thin as a Popsicle stick has to withstand all of that pull.”

Strings, woods and their sounds
“Throughout history there have been 3 kinds of strings used for the guitar. Originally cat gut- which is actually sheep intestines was the first kind of string. Then Nylon which is plastic, then metal strings. Each of these produces a specific and unique sound. Cat gut has a soft and pleasant sound. Nylon that was used in the 1930s and 1940s when plastic became popular was a little louder. Finally, we have metal strings which are much louder because they vibrate the soundboard much more.

Strings by themselves don’t make very much noise. You can find that out by pulling a rubber band apart and tweaking it. You will hear a little bit of sound, but not very much. The same thing applies to the strings on a guitar. In order to amplify the sound on an acoustic guitar there is a soundboard on top and as that vibrates it projects sound out into the air. The more vibrations the louder the guitar becomes. Also depending on what the soundboard is made of - spruce, maple, etc. - it resonates differently. Each element of the guitar produces a different kind of sound.

Historically, acoustic guitars have been made of Spruce and Brazilian Rosewood. But Brazilian Rosewood is an endangered wood species and it can't be brought into America any more. We are now looking at things like carbon fiber to take the place of that kind of wood which resonates very nicely on the sides and backs of the guitar. For electric guitars – the sky’s the limit - Mahogany, Maple, all kinds of different woods and materials like acrylic and aluminum. We even have a guitar in the exhibition that is made using a 3-D printer.”

Evolution of the Electric Guitar - Make it Louder!
“The history and evolution of the guitar is in many ways the history of trying to make the instrument louder. Guitars were built bigger in size, but thinner wood was used to increase the vibrations. Still by the time the 1900's rolled around, the guitarists in bands weren’t able to hear themselves over horns, trumpets, drums, and pianos. So the desire to create a guitar that would actually be as loud as, or in many cases louder than, these instruments drove the creation of the electric guitar.

At first, guitarists used horns and modified cones around the guitar itself to amplify the sound. Beginning in the 1930's, inventors used electricity to amplify the strings themselves with the assistance of a magnetic pickup.

The electric guitar works on a very simple electromagnetic principle. Metal strings - and they must to be metal, not plastic – vibrate above a pickup, which is a magnet wound with copper wire. The vibrations cause a disturbance in the magnetic field around the pickup. These disturbances are transmitted to an amplifier as electric signals. The entire process results in sound coming out of amplified speakers. When this happens, the guitar becomes one of the loudest devices ever created.”

Who do you consider to be the most famous inventor of the guitar?
“Perhaps the most famous inventor in electric guitar circles is Leo Fender, whose name graces the most famous guitars in the world- the Telecaster and the Stratocaster.

One thing that most people don’t know about Leo is that he was a radio repairman. And even though he invented a guitar that’s considered a staple of players all around the world, he never learned how to play or tune one.”

What’s next for The National GUITAR Museum?
“The plan is to tour the country for the next several years and at the end of those years look back at the differenct cities we’ve been to and decide which one would be the best place for a permanent home of the National GUITAR Museum.”

Want to know more about the band Goldrush?
Goldrush is a four piece rock and roll band made up of acoustic instruments - a violin, a contrabass,a drum set and a guitar. Their music is a fusion of classical orchestral instruments with contemporary instruments. The band members include Treesa Gold on the violin, Matt Gold on the contrabass, Greg Butler on drums, and Prabir Mehta on guitar. I asked Prabir to tell me about what inspired him to pick up that first guitar? He shared that it was hearing Creedence Clearwater Revival’s “Fortunate Son” for the first time as a young child when he moved to the U.S. “When I heard that guitar come in for the first time – every hair on my body just stood up. It’s kind of cool as a listener to be able to get that kind of feeling out of a guitar and as a performer to try to play well enough so that response can happen to someone else.”

Prabir, what do you think the guitar of the future will be like?
“In the future – guitars may be without strings or they may have even more strings. The weight of the guitar and the materials could change. It just depends on what purpose needs to be filled.”

What do you think the guitar of the future will be like? How will science continue to play a role in its evolution? I can’t wait to find out.